When combined with centrifugal force acting on the liquids, the Virtual Laser Valve (VLV) enables the two fundamental liquid handling operations: metering a well-defined volume of liquid and moving the liquid to a well-defined destination.
Dosimeter
The dosimeter is the VLV-based microfluidic component used to meter liquid volumes. It consists of a chamber on one side of the base and one or more channels on the other side of the base. The channels are oriented in the direction of the centrifugal force acting on the liquid. Initially, liquid is contained in the chamber. The VLV then creates a connection between the chamber and one of the channels. The volume of liquid which will flow through this connection is precisely determined by the cross section of the chamber multiplied by the difference between the initial and resulting liquid level. If the initial liquid level is not known, it can be defined by first creating a VLV, with the excess liquid purged.
The dosimeter can be thought of as a plastic bottle into which a first hole is made to let excess liquid flow out. By making a second hole below the first at a specified distance, the volume of liquid flowing through the second hole is determined by the distance between the two holes, multiplied by the cross section of the bottle.
